Newest Threads

**JayC** · 08-24-2008, 01:24 PM

I'm planning on (dreaming about) putting together a HERMS. Appropriate pumps have seemed expensive, now that all of my student loans are now due. I found this, and it seems like it would be great. It's only a hand pump, but it shouldn't be too difficult to motorize. That and it's cheap. Amazon has it available at something like $6-7. The inner tubing is replacable, which is great, because it's designed for radio control airplane fuel, and I wouldn't assume it's food safe. But, a little silicone tubing, and it seems like you'd be in business. One potential drawback is that it says the ideal pumping speed is 60 rpm, and that 1 revolution pumps 0.6 oz, which equates to a little over 1/4 gpm. This seems slow compared to what little I know about HERMS. But, maybe their "ideal" is low, and I could just up the rpm's and see what happens? That and they're marketing to folks who are used to moving smaller volumes, so they've had no incetive to brag about moving 1 gpm. The difference in tubing flexibility and/or diamter may make a difference as well. I'm thinking that for the price, if I can't get it to work, I've still spent less than I would going to a movie.

http://www.dbproducts.com/downloads/pdf/ss_tech_sheet.pdf
http://www.dbproducts.com/downloads/pdf/ssgl_manual.pdf

LayMeister · 08-24-2008, 02:00 PM

This is a very cool find. I am anxious to see how you motorize it. Please keep us posted.

Paul

edbees · 08-24-2008, 02:14 PM

Thanks for the info, I've been looking for a small pump like this! I found this info, it seems it comes with a silicone pumping element already, http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXB887&P=0#tech

**beerthirty** · 08-24-2008, 02:34 PM

Do they have a motor for it? The accessories list a charger and starter stand. I would a wiper motor or the like could motorize it but the crank arm would need to be the exact length so that you did not side load the nylon shaft causing excessive wear or breaking it. good luck

Laurel · 08-24-2008, 02:45 PM

I think making a gear drive system that hooks up to a drill would probably be an easier option.

**JayC** · 09-07-2008, 09:56 AM

Yeah, the one for glow fuel does come with a silicone pump element, but it's pretty small. It only goes up to the top of the inside of the pump, and then each side connects to a small nipple that passes through the body of the pump. The outlet of the nipple is about 1/16 of an inch. So I pulled them. I've got the innards of the pump on display below (if I upload the pics right). The holes at the top of the pump that the nipples went through are only about 5/16 of an inch, so I'm hoping to drill those out, and just pass a longer/wider silicone tube through it. I've got a hairbrained scheme to motorize it, I'll let you know if it works.

http://www.homebrewtalk.com/gallery/showphoto.php?photo=13266&size=big&cat=all&ppuser= 16059
http://www.homebrewtalk.com/gallery/showphoto.php?photo=13267&cat=all&ppuser=16059

**JayC** · 09-07-2008, 10:36 AM

Looking at tubing on McMaster-Carr. I'm not sure whether to order the braided-reinforced silicone tubing, or the plain stuff. Since near-boiling water will be passing through it, and the max pressure of the unreinforced tubing is only 10 psi at 72 degrees, I think I'm going to go with the reinforced tubing. I'm just concerned that the braiding will interfere with the rollers on the pump working.

**beerthirty** · 09-07-2008, 11:57 AM

I've never seen reinforced silicone tubing, but it should work fine. The reinforcement keeps the tube from expanding not collapsing. Eventually the threads will saw through the tube from constant working so I would keep a spare piece on hand.

Joe Camel · 09-07-2008, 06:26 PM

Most peristaltic pumps have a fixed occlusion, or gap between the walls and the rollers, so the tubing you use should have walls that are half the thickness of the occlusion gap. That way, the rollers will pinch the tubing effectively, if the tubing walls are too thin, you'll get fluid slippage and too thick, you'll stall your pump or not get any fluid in at all.

Use the tubing that comes with it as a guide and only get tubing with the same dimensions. If you want to slow the pump down, you can use a smaller diameter tubing with the same wall thickness. Platinum cured silicone is very good with little leaching, but a very high oxygen transfer rate. You might be better served looking at Pharmed. Masterflex Pump Systems - Tubing pumps and Peristaltic Pumps for Sanitary Fluid Handling has a lot of good information on tubing types.

Peristaltic pumps are very good and generally keep your wort clean and safe, but you have to keep an eye on the tubing, especially at high temperatures. When it fails, it fails spectacularly.

Cheers

**JVD_X** · 09-08-2008, 04:36 PM

I would also be cautious about using such a thin diameter hose... I could see it getting easily clogged with protiens, hops, or grains.